Skin cancer may be an epidemic; doctors warn that sunscreen use is spotty

Washington Post 4 May 2010

Carolyn Butler

Readers, I am red-faced on multiple levels: It's only the first week of May, and I've already got my first sunburn of the season. And before you ask: Yes, I am well aware that ultraviolet rays have been proven to cause skin cancer, not to mention wrinkles and other signs of premature aging. Blame the combination of a little bit of laziness, a lack of easily accessible sunscreen -- and the ability to convince myself, despite all evidence to the contrary, that it really wasn't that bright outside.

That said, I really have no excuse. If any of us needed another reason to slather on the SPF 50, two studies published in the March Archives of Dermatology provide the best estimate yet of the significant -- and steadily growing -- prevalence of non-melanoma skin cancers in this country. While these cancers are rarely fatal and extremely treatable if caught early, they are not entirely harmless, and many experts worry that non-melanoma skin cancers are becoming epidemic.

Consider some recent studies: First, a Harvard researcher developed a mathematical model that found that more than 13 million white, non-Hispanic people living in the United States in 2007 had had at least one non-melanoma -- primarily either basal cell or squamous cell carcinoma. In a second, more in-depth study, Connecticut dermatologist Howard Rogers and colleagues at several medical schools dug into two Medicare databases and found that the number of procedures to treat such skin cancers ballooned nearly 77 percent between 1992 and 2006, to some 2 million cases annually. Using additional federal survey data, the researchers deduced that the occurrence of non-melanomas had grown from about 900,000 to 1.2 million in 1994 -- when the last national estimate was done -- to more than 3.5 million cases in 2006.

Why the guessing games? Unlike melanomas, non-melanomas currently aren't reported to national cancer registries, so it's impossible to gauge just how widespread they are.

"We don't know exactly what we're dealing with, but many people in the field believe this new number is still an underestimate of the burden of disease," says dermatologist Suraj Venna, director of the melanoma center at the Washington Cancer Institute at Washington Hospital Center. He adds that recent research has shown that cases of the far less common but much more deadly melanomas are also on the rise, particularly among white women between the ages 15 and 39. "What we do know, for sure, is that there has been a tremendous burst in skin cancer, period; that UV rays are a primary cause; and that there is absolutely no such thing as a safe tan."

Rogers believes that we're just seeing the tip of the iceberg, as a lag time between sun exposure and the emergence of skin cancer means that sun worshipers of yore, who came of age when basting yourself with baby oil was the norm, are only now beginning to suffer the medical consequences of all that tanning. "We know [from this research] that non-melanomas are, on average, increasing by over 4 percent per year, with no sign of slowing down," he says.

But while it's been clear for well over 15 years that we should protect our skin as much as possible from UV rays -- which have been declared a known human carcinogen by both the Department of Health and Human Services and the International Agency for Research on Cancer -- the allure of a golden glow remains strong, particularly among young people. A recent survey of 18,000 Seventeen magazine readers found that while 90 percent of them think it's important to use sunscreen, just 12 percent apply it every day and only 30 percent use it at the beach; 80 percent consider themselves more attractive with a tan. "The medical community has failed, to some extent, because we've made what we thought were strong efforts to educate the public [about the dangers of UV rays from all sources], but for some reason we've missed the boat with certain groups -- especially young women," says Venna.

For those of us who need a refresher course in sun protection, it's important to know that genetics do play a role in the development of skin cancer, "but intentional excessive UV exposure is the most modifiable risk factor," says Venna. He cites protective measures you've likely heard before: limiting time in the sun during daylight hours, avoiding tanning booths and diligently using sunscreen, sunglasses, hats and umbrellas. He also recommends clothing with built-in UV protection.

If you're confused about the seemingly ongoing question of how high is high enough, when it comes to SPF, Rogers says not to believe to old adage that any number higher than 30 provides little to no additional UV protection. "The reality is that we have new and better sunscreens coming out all the time, and the new data that's come out has really indicated that with typical use, sunscreens that have a very high SPF provide significantly greater protection than the 15s and 30s," says the dermatologist, who uses an SPF 70 with Helioplex, a relatively new ingredient that prevents sunscreen from degrading quickly.

However, both he and Venna warn that even the highest SPF number doesn't mean anything if you're not using the proper amount of sunblock or reapplying it enough. "Research has shown that the majority of us use sunscreen inefficiently, so we're getting a false sense of security," says Venna, who recommends slathering your body with the equivalent of two shot glasses full of a broad-spectrum lotion with a minimum SPF of 50, which blocks 98 percent of harmful UV rays. Reapply it every two to three hours, he says, and more frequently after activities such as exercise and swimming.

And how about those of us who get lazy every now and then and pay the price with a burn, or whose noses peeled at least a handful of times every summer as children?

Experts stress that it's never too late to get proactive about sun protection, including having any suspicious mole or freckle checked out. "The truth is that UV damage causes cumulative effects on the DNA in skin cells, and therefore, if someone limits UV exposure at age 30, that will have a beneficial effect over time," says Venna. "It's analogous to the risk of lung cancer and smoking: I tell all my patients, 'If you've been smoking since you were 20 and stop at 40, you will decrease your risk of lung cancer by the time you're 60.' Changing your behavior at any point definitely makes a difference."